1. Field of the Invention
The present invention relates to valves and, more particularly, to a device and method for detecting and monitoring media leakage from a valve.
2. Description of Related Art
Valves used in applications involving media flow, i.e., fluid and/or gas flow, are well known in the art. Valves are used to restrict and/or isolate media flow, often through a pipeline. Typically, a valve includes a stem that enters the body of the pipeline which when connected to a disc can stop media flow. Based on positioning of a disc, media flow can start, stop, or be regulated. Oftentimes, the valve is sealed with a packing material around the stem to prevent leakage of media. Preferably, packing is a malleable compound adapted to seal a valve stem when tightened. The characteristics of the packing must be both strong and hard enough to hold the pressure of media in the valve, but yet soft enough to be compressed into shape.
While valves are helpful in regulating media flow in a pipe, they also can be destructive if allowed to degrade to a condition where external leakage can occur. As the stem of the valve is stroked, or moved, the packing can slowly wear away. This wearing away or other degradation can create gaps in the packing, which can cause the valve to become loose, losing the ability to contain pressurized media, and thus media within the pipe can escape. The result of such escaping media includes the possible release of valuable material and can, in many circumstances, be extremely dangerous. For example, a pipeline can contain a toxic flow, wherein leakage could result in disastrous consequences, including possible fatalities.
Some devices and methods are available to help detect an existing leak in the valve. For instance, U.S. Pat. No. 6,168,161 to Majcen discloses a rotary valve shaft seal. A seal having spacers is positioned between a packing and a valve body, wherein the spacers enable adjustment of the packing. The spacers have a predetermined thickness, which permit the maximum tightening of the packing. Furthermore, the spacers permit the exertion of the maximum pressure on the packing fasteners. Majcen uses linear motion to adjust the device. While Majcen indicates that the packing is worn, it fails to indicate when the packing wears. The disastrous consequences of a leaking valve are still possible even with Majcen.
U.S. Pat. No. RE34923 to Ruesch describes a valve stem seal leak protection and detection apparatus. This invention discloses an indicator that provides information relating to actual leakage of media. In order for the indicator to operate, pressure pushes through the packing. Thus, there is a leak. Unfortunately, Ruesch requires an actual leak to occur before the leak can be identified.
Currently, leaks in and around a packing of valves can and do go undetected. What is needed, therefore, is a leak prevention device that can indicate that a leak is forthcoming, rather than a leak has occurred. Additionally, the device would be beneficial if it can be directly attached to a valve.